Discharge containers molded by blow molding are well known and are generally called the delaminated bottles. Such a bottle comprises an outer layer that has been formed in a given shape and has a high ability to retain its own shape, an inner layer in the shape of a highly flexible pouch laminated to the outer layer in an easily peelable manner, a neck, which is disposed in the upper portion of the container and is used as a discharge port for the contents, and an air intake port for introducing outside air into the interspace between the outer and inner layers.
The blow-molded and laminated discharge container is molded by extrusion-molding laminated parison obtained from the co-extrusion of an outer-layer parison and an inner-layer parison having little compatibility with each other, holding tight and pressing the bottom with the pinch-off part of the blow-molding tool to adhere or attach the laminates to each other, and blow-molding the laminated and bottomed parison. Basically, the bottom seal has the laminated structure comprising the outer layer and the inner layer, which are scarcely compatible with each other. Naturally, sometimes there occurs a bottom crack in the outer layer.
If this bottom crack develops, a slit is formed in the bottom of the discharge container. As a result, the container bottom would have weak mechanical strength. If the container is used in the environment where much water is used, then water may inconveniently pass through the slit into the interspace between outer and inner layers concurrently with the peeling and deflation of the inner layer.
Conventionally, these problems have been dealt with by utilizing a special pin or an adhesive layer, which strongly fusion-bonds or adheres the outer and inner layers of the bottom seal so that cracking in the bottom seal can be prevented from occurring. Instead, an air intake port was opened by exclusive processing in the neck or in the outer layer of the body of the discharge container. In this manner, the bottom of the molded discharge container could have high and stable mechanical strength. In addition, the air intake port was disposed at a place capable of introducing outside air smoothly without giving damage to the outer appearance of the discharge container.
In the meantime, an air intake hole can be molded quite simply and reliably when the slit is opened by the cracking in the bottom seal and is used to serve as the port for introducing outside air into the interspace between the outer layer and the inner layer. Inventions utilizing such a slit are known in the art. See, for example, Patent Document 1, in which a base cup is fitted around the bottom cylinder of a discharge container. The base cup is provided with a pushing section to push the sidewall of the bottom cylinder of the container. At the time when the base cup is fitted around the bottom cylinder of the container, the force pushing the bottom cylinder is conveyed to the bottom seal, and a crack develops in the outer layer. The slit thus formed can be used to serve as the air intake hole.
[Patent Document 1] Publication No. P1997-301404
In the case of the container made of soft materials, it may happen that the base cup cannot be fixed to the bottom of the container with sufficient fitting force.
The object of this invention is to solve the above-described problems and to provide a discharge container which has a base cup fitted tightly around the bottom cylinder of the container and in which the bottom seal can be cracked reliably so that a slit is formed easily and reliably for the introduction of outside air into the interspace between the outer layer and the inner layer.